Gaps in tropical science arising from biased spatial patterns of sampling and citation

Effective environmental policies for the tropics depend on robust, representative scientific data. However, the extent to which existing field research accurately represents the vast environmental diversity of this critical region remains largely unexplored. Although, there is strong evidence from particular disciplines and regions that existing research is patchily distributed ^1–9 . Here, we show how biases in sampling and citation over space and across key environmental gradients ^10–14 from all disciplines for the entire tropics may lead to unrepresentative scientific paradigms and inappropriate policy prescriptions. We mapped sampling locations and citations from 2 738 published studies in natural terrestrial tropical environments across all disciplines to identify gaps in field sampling effort and research attention ^15,16 . Five ecoregions – all in moist broadleaf forests – generated 22% of the total citations but covered only 3% of the tropical land area. By contrast, drier biomes with low tree cover accounted collectively for 57% of the tropical area but generated only 20% of total citations. Locations that are drier, colder, with greater plant species richness, lower tree cover and facing greater climate change extremes were under-sampled and under-cited. Our results help to target efforts to correct these imbalances to improve the scientific basis for environmental policies across the tropics.